@jexs/mcp

Model Context Protocol server that lets Claude Code, Claude Desktop, and other MCP-aware tools introspect and evaluate Jexs templates as you author them.

The server dynamically discovers whichever @jexs/* packages are installed in the project it's run from, so you only get tools for the nodes you actually have.

Part of Jexs.

Install

You usually don't install this manually — wire it into your MCP-aware editor and it runs via npx. If you do want it as a project dev dep:

npm install -D @jexs/mcp

Use with Claude Code

Add to your project's .mcp.json:

{
  "mcpServers": {
    "jexs-dev": {
      "command": "npx",
      "args": ["-y", "jexs-mcp"]
    }
  }
}

Claude Code will spawn the server in your project's working directory and discover its installed @jexs/* packages.

Use with Claude Desktop

Add to claude_desktop_config.json (path varies per OS — see Claude Desktop docs):

{
  "mcpServers": {
    "jexs-dev": {
      "command": "npx",
      "args": ["-y", "jexs-mcp"],
      "cwd": "/absolute/path/to/your/jexs/project"
    }
  }
}

Exposed tools

• list_nodes — list every node (and its operation keys) from the installed @jexs/* packages, read from each node class's static schema.
• describe_op — return the static schema entry for a given operation (description, examples, siblings).
• inspect_file — load a .json template from the project and parse-check it.
• resolve_expression — evaluate a JSON expression against a context and return the result. Useful for verifying behavior without spinning up a full server.

License

MIT